1 . Field of the Invention
This invention relates to a fuel injector mounting construction for an in internal combustion engine, and more particularly to an improved fuel injector mounting construction on a direct injected engine that can securely hold a fuel injector notwithstanding manufacturing tolerances.
2. Description of Related Art
In all fields of engine design, there is an increasing emphasis on obtaining more effective emission control, better fuel economy and, at the same time, continued high power output. This trend has resulted in the substitution of fuel injection systems for carburetors as the engine charge former. In the common systems used, fuel is injected into an intake air manifold. In order to obtain still further improvement, direct injection systems are being considered. These systems inject fuel directly into the combustion chamber and thus have significant potential advantages such as fine emission control.
An injection nozzle of a fuel injector employed in a conventional direct injection system is exposed to a combustion chamber through an opening formed in a cylinder head assembly. A forked member usually is used to affix the fuel injector onto the cylinder head assembly. The forked member is secured to the cylinder head assembly with a fastener such as a bolt. Meanwhile, the forked member contacts the body of the fuel injector with its forked section to push a flange of the fuel injector toward the combustion chamber so that the injection nozzle of the fuel injector can be exposed to the combustion chamber.
The fuel injector often has a mount section between the flange and the injection nozzle. This mount section has a diameter larger than a diameter of the injection nozzle but smaller than a diameter of the flange.
The cylinder head opening includes two sections: a small diameter opening section and a large diameter opening sections. A generally square step occurs at the transition between the two opening sections.
The mount section of the fuel injector is seated at this step portion and loaded by the forked member. A seal member, such as a disc spring, conventionally is provided between the mount section of the fuel injector and the step portion to seal up this area.
On occasion, the loading on the fuel injector and thus on the seal can be non-uniform around the seal and can be less than a desired loading. The effectiveness of the seal thus is jeopardized. This occurs because the configuration of the forked member and the surface of the cylinder head on which it is mounted vary due to manufacturing tolerances. If these tolerances stack-up adversely, the forked member does not squarely load the fuel injector, and thus the loading around the seal is not uniform. At the extreme, the fuel injector can assume a noticeably skewed orientation relative to a central axis of the opening in which is mounted.
Hot gases and flames can leak through the seal if the fork member does not properly load the fuel injector and compress the seal. That is, if the seal is not uniform and one section of the seal is not properly compressed, hot gases and flames will leak through the improperly loaded section of the seal. The injector nozzle consequently is excessively heated and deposits can form on the nozzle. These deposits can block and clog the nozzle apertures thereby preventing proper fuel injection and effecting engine performance and emission control.